Avaliação da eficiência de desemulsificantes na quebra de emulsões de petróleo utilizando técnicas combinadas de planejamentos de misturas e fatorial

Abstract

The presence of produced water in association with oil represents one of the most significant challenges faced by the oil and gas industry. Although conventional physical methods, such as heating and the application of electric fields, are effective in promoting oil dehydration, the high operational costs associated with intensive energy consumption justify the use of demulsifiers. These chemical agents work synergistically with physical processes, reducing energy consumption. However, the effectiveness of these additives depends on specific conditions, such as component ratios, process temperature, and formulation concentration. The determination of these optimal conditions is traditionally conducted through trial and error experimentation, often leading to costly and time-consuming results. To address these limitations, the present study employs a Design of Experiments (DOE) approach as a methodological tool for the systematic design and execution of demulsification tests, facilitating a more efficient and cost-effective process analysis. Two sequential experimental designs were implemented. The first involved a mixture design aimed at determining the optimal proportions of formulation components, which included two commercial demulsifiers: an EO/PO copolymer (ethylene oxide/propylene oxide) and alkoxylated resin, with xylene used as a diluent. Subsequently, additional demulsification tests were designed based on a 2² factorial design to determine the optimal temperature and concentration conditions for maximizing demulsification efficiency. Efficiency was assessed using the Bottle Test, in which the mixture design tests were conducted under fixed operational conditions recommended by the reagent suppliers, utilizing 300 ppm of demulsifiers at a temperature of 75 ºC. For factorial design, operational conditions were evaluated within temperature ranges of 55 ºC to 75 ºC and demulsifier concentrations from 300 ppm to 900 ppm. Based on the results obtained from the Bottle Test, two statistically significant mathematical models were developed. The highest water separation efficiency (91.02%) was achieved with Formulation J, which consisted of 67% alkoxylated resin, 17% EO/PO copolymer, and 17% xylene. In the 2² factorial design, the optimal operational conditions for this formulation were identified at a concentration of 300 ppm and a temperature of 75 ºC, resulting in a water separation efficiency of 91.34%.